Problem: $ { {4} \times \left[\begin{array}{rr}{-2} & {0} \\ {1} & {-1} \\ {3} & {3}\end{array}\right] = {?} } $
To multiply a matrix by a number, multiply each item of the matrix by the number. ${\left[\begin{array}{rr}{4}\times{-2} & {4}\times{0} \\ {4}\times{1} & {4}\times{-1} \\ {4}\times{3} & {4}\times{3}\end{array}\right]}$ Now, simplify: ${\left[\begin{array}{rr}{-8} & {0} \\ {4} & {-4} \\ {12} & {12}\end{array}\right]}$